/*
 * In-Field Label jQuery Plugin
 * http://fuelyourcoding.com/scripts/infield.html
 *
 * Copyright (c) 2009 Doug Neiner
 * Dual licensed under the MIT and GPL licenses.
 * Uses the same license as jQuery, see:
 * http://docs.jquery.com/License
 *
 * @version 0.1
 */
(function($) {

    $.InFieldLabels = function(label, field, options) {
        // To avoid scope issues, use 'base' instead of 'this'
        // to reference this class from internal events and functions.
        var base = this;

        // Access to jQuery and DOM versions of each element
        base.$label = $(label);
        base.label = label;

        base.$field = $(field);
        base.field = field;

        base.$label.data("InFieldLabels", base);
        base.showing = true;

        base.init = function() {
            // Merge supplied options with default options
            base.options = $.extend({}, $.InFieldLabels.defaultOptions, options);

            // Check if the field is already filled in
            if (base.$field.val() != "") {
                base.$label.hide();
                base.showing = false;
            };

            base.$field.focus(function() {
                base.fadeOnFocus();
            }).blur(function() {
                base.checkForEmpty(true);
            }).bind('keydown.infieldlabel', function(e) {
                // Use of a namespace (.infieldlabel) allows us to
                // unbind just this method later
                base.hideOnChange(e);
            }).change(function(e) {
                base.checkForEmpty();
            }).bind('onPropertyChange', function() {
                base.checkForEmpty();
            });
        };

        // If the label is currently showing
        // then fade it down to the amount
        // specified in the settings
        base.fadeOnFocus = function() {
            if (base.showing) {
                base.setOpacity(base.options.fadeOpacity);
                base.$label.hide();
            };
        };

        base.setOpacity = function(opacity){
        //base.$label.stop().animate({ opacity: opacity }, base.options.fadeDuration);
        base.showing = (opacity > 0.0);
        };


        // Checks for empty as a fail safe
        // set blur to true when passing from
        // the blur event
        base.checkForEmpty = function(blur) {
            if (base.$field.val() == "") {
                base.prepForShow();
                base.setOpacity( blur ? 1.0 : base.options.fadeOpacity );
            } else {
                base.setOpacity(0.0);
                base.$label.hide();
            };
        };

        base.prepForShow = function(e) {
            if (!base.showing) {
                // Prepare for a animate in...
                //base.$label.css({opacity: 0.0}).show();
                base.$label.show();
                // Reattach the keydown event
                base.$field.bind('keydown.infieldlabel', function(e) {
                    base.hideOnChange(e);
                });
            };
        };

        base.hideOnChange = function(e) {
            if (
				(e.keyCode == 16) || // Skip Shift
				(e.keyCode == 9) // Skip Tab
			  ) return;

            if (base.showing) {
                base.$label.hide();
                base.showing = false;
            };

            // Remove keydown event to save on CPU processing
            base.$field.unbind('keydown.infieldlabel');
        };

        // Run the initialization method
        base.init();
    };

    $.InFieldLabels.defaultOptions = {
        fadeOpacity: 0.5, // Once a field has focus, how transparent should the label be
        fadeDuration: 300 // How long should it take to animate from 1.0 opacity to the fadeOpacity
    };


    $.fn.inFieldLabels = function(options) {
        return this.each(function() {
            // Find input or textarea based on for= attribute
            // The for attribute on the label must contain the ID
            // of the input or textarea element
            var for_attr = $(this).attr('for');
            if (!for_attr) return; // Nothing to attach, since the for field wasn't used


            // Find the referenced input or textarea element
            var $field = $(
				"input#" + for_attr + "[type='text']," +
				"input#" + for_attr + "[type='password']," +
				"textarea#" + for_attr
				);

            if ($field.length == 0) return; // Again, nothing to attach

            // Only create object for input[text], input[password], or textarea
            (new $.InFieldLabels(this, $field[0], options));
        });
    };

})(jQuery);